Arithmetic Coding Example

• P(a) = 1/4, P(b) = 1/2, P(c) = 1/4

• C(a) = 0, C(b) = 1/4, C(c) = 3/4

• abca

symbol w l r

0 1

a 1 0 1/4

b 1/4 1/16 3/16

c 1/8 5/32 6/32

a 1/32 5/32 21/128

tag = (5/32 + 21/128)/2 = 41/256 = .001010010...

l = .001010000...

r = .001010100...

code = 00101

prefix code = 00101001

w := r - l;

l := l + w C(x);
r := l + w P(x)

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